Hi, I made a microphone circuit using the schematic:Electronics Projects For Dummies Parabolic Microphone and was successful and fun on a breadboard. I then wanted to make this smaller - i.e. on a PCB but i had no luck. I had my college etch a board for me which i checked was ok, but he circuit didnt work, and then I recreated the design on a matrixboard joined with copper tracks.

What could be the issue? I tooked the components apart and recreated them on a breadboard and it works fine again

Also, regarding the copper track i use (it is copper tape) - how do I join the tracks? the adhesive is acrlyic and non conudcive and i have to join them by painting some leitsilber l100 over it and its very annoying

OH wow...
even though thats true im pretty sure i paced the compoents properly but who am i to say that
I thought the circuit was wrong so i pulled all the copper tapes off the board so i could reuse it for something else, but ill do it again and carfully place the components this time and let you know how it goes.
Do the tracks seem OK though?
thanks a lot btw

when i printed the track out i rememebered to mirror it. i can hold both components and track printouts back to back and they fit on each other as they should. thanks though. let me get out of bed and carry on recreating the track

im a bit new to all of this, which is why i only make projects that i find rather than design my own (im only 18 and hope to start an electronics eng. degree this coming academic year)
but despite that i clearly love my subject and enjoy learning ahead.
what difference does a polarised cap make? and how is their use over a non-polarised decided?
i just know basics how they store charge, time constant, only ac currents can pass etc etc.. but id go to say i no practically nothing atm

Polarity of a capacitor generally only affects its lifespan. Electrolytic capacitors are designed so that they only work one way round... and they can catastrophically fail if they are reversed. That means they can explode, leak, and sometimes catch fire especially for tantalum capacitors. I don't quite remember the reason, but it's more expensive to make non-polar electrolytics, and it makes them bigger in size. In most cases polarity is not an issue, because electrolytics are often used to filter DC voltages and not much else. They have some applications in timing circuits and in a.c. coupling applications too, but their imperfect behaviour (e.g. dielectric absorption, polarity) makes them perform poorly.

oh ok, that helped a bit. So i guess i was lucky my circuit only needs 6V and i didnt leave it on too long when i most likely had that cap backwards
thanks a lot guys!
now to remove the hissing in the background! any suggestions? or is that inevitable with audio circuits as simple as this?